421 research outputs found
Feshbach resonances and weakly bound molecular states of boson-boson and boson-fermion NaK pairs
We study theoretically magnetically induced Feshbach resonances and
near-threshold bound states in isotopic NaK pairs. Our calculations accurately
reproduce Feshbach spectroscopy data on NaK and explain the origin of
the observed multiplets in the p-wave [Phys. Rev. A 85, 051602(R) (2012)]. We
apply the model to predict scattering and bound state threshold properties of
the boson-boson NaK and NaK systems. We find that the NaK
isotopic pair presents broad magnetic Feshbach resonances and favorable
ground-state features for producing non-reactive polar molecules by two-photon
association. Broad s-wave resonances are also predicted for NaK
collisions.Comment: 39 pages, 15 figures. Phys. Rev. A in pres
Polar molecule reactive collisions in quasi-1D systems
We study polar molecule scattering in quasi-one-dimensional geometries.
Elastic and reactive collision rates are computed as a function of collision
energy and electric dipole moment for different confinement strengths. The
numerical results are interpreted in terms of first order scattering and of
adiabatic models. Universal dipolar scattering is also discussed. Our results
are relevant to experiments where control of the collision dynamics through one
dimensional confinement and an applied electric field is envisioned.Comment: 25 pages, 13 figure
On Safety Assessment and Base Isolation of Heavy Non-structural Monolithic Objects
Abstract Under seismic actions heavy non-structural objects, which are usually placed at the top of existing constructions, may constitute a danger to human lives and a considerable loss for world heritage. In this contribution, safety assessment of non-structural monolithic objects is discussed through the illustration of a case study, which concerns seismic protection of eleven ancient marble decorative pinnacles placed at the top of a three-arched masonry city gate in Ferrara (ITALY). A method for assessing the safety of the underlying masonry structure under the action of seismic excitations is outlined and the amplification of the ground motions due to the presence of such structure is evaluated
Co-digestion of macroalgae for biogas production: an LCA-based environmental evaluation
Algae represent a favourable and potentially sustainable source of biomass for bioenergy-based industrial pathways in the future.
The study, performed on a real pilot plant implemented in Augusta (Italy) within the frame of the BioWALK4Biofuels project,
aims to figure out whether seaweed (macroalgae) cultivated in near-shore open ponds could be considered a beneficial aspect as a
source of biomass for biogas production within the co-digestion with local agricultural biological waste. The LCA results
confirm that the analysed A and B scenarios (namely the algae-based co-digestion scenario and agricultural mix feedstock
scenario) present an environmental performance more favourable than that achieved with conventional non-renewable-based
technologies (specifically natural gas - Scenario C). Results show that the use of seaweed (Scenario A) represent a feasible
solution in order to replace classical biomass used for biofuel production from a land-based feedstock. The improvement of the
environmental performances is quantifiable on 10% respect to Scenario B, and 38 times higher than Scenario
Direct evaporative cooling of 39K atoms to Bose-Einstein condensation
We report the realization of Bose-Einstein condensates of 39K atoms without
the aid of an additional atomic coolant. Our route to Bose-Einstein
condensation comprises Sub Doppler laser cooling of large atomic clouds with
more than 10^10 atoms and evaporative cooling in optical dipole traps where the
collisional cross section can be increased using magnetic Feshbach resonances.
Large condensates with almost 10^6 atoms can be produced in less than 15
seconds. Our achievements eliminate the need for sympathetic cooling with Rb
atoms which was the usual route implemented till date due to the unfavourable
collisional property of 39K. Our findings simplify the experimental set-up for
producing Bose-Einstein condensates of 39K atoms with tunable interactions,
which have a wide variety of promising applications including
atom-interferometry to studies on the interplay of disorder and interactions in
quantum gases.Comment: 7 pages, 6 figure
Il sistema giudiziario Ucraino al vaglio del consiglio d'Europa
La scelta di un sistema appropriato per procedere alle nomine
giudiziarie1 costituisce uno delle principali difficoltĂ ai quali si scontrano
le nuove democrazie, spesso preoccupazioni per l’indipendenza e
l’imparzialità politica del potere giudiziario. I’intervento del potere
politico nella procedura di nomina, compromette la neutralitĂ della
giustizia in questi stati, tant’è che in altri paesi, particolarmente in questi
, dove il sistema giudiziario ha fatto da testimone del suo carattere
democratico; tali metodi nomina sono considerati efficaci e. Le norme
internazionali a riguardo sono piuttosto favorevoli alla depoliticizzazione
generale; non esistono tuttavia dei modelli unici di nomina potendo,
assicurare in maniera ideale, dei principi della separazione del potere e
l’indipendenza del potere giudiziario
Accurate near-threshold model for ultracold KRb dimers from interisotope Feshbach spectroscopy
We investigate magnetic Feshbach resonances in two different ultracold K-Rb
mixtures. Information on the K(39)-Rb(87) isotopic pair is combined with novel
and pre-existing observations of resonance patterns for K(40)-Rb(87).
Interisotope resonance spectroscopy improves significantly our near-threshold
model for scattering and bound-state calculations. Our analysis determines the
number of bound states in singlet/triplet potentials and establishes precisely
near threshold parameters for all K-Rb pairs of interest for experiments with
both atoms and molecules. In addition, the model verifies the validity of the
Born-Oppenheimer approximation at the present level of accuracy.Comment: 9 pages, 7 figure
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